<template>
  <div>
    <router-link tag="div" to="/" class="header-abs">
      <span class="iconfont header-abs-back">&#xe624;</span>
    </router-link>
    <div class="header-fixed" v-show="!showAbs" :style="opacityStyle">
        <router-link to="/">
            <span class="iconfont header-fixed-back">&#xe624;</span>
        </router-link>
        景点详情
    </div>
  </div>
</template>

<script>
export default {
  name: 'DetailHeader',
  data () {
    return {
      showAbs: true,
      opacityStyle: {
        opacity: 0
      }
    }
  },
  methods: {
    handleScroll (e) {
      const top = document.documentElement.scrollTop
      if (top > 60 && top < 140) {
        let opacity = top / 140
        this.opacityStyle = {
          opacity
        }
      }
      if (top > 60) {
        this.showAbs = false
      } else {
        this.showAbs = true
      }
    }
  },
  activated () {
    window.addEventListener('scroll', this.handleScroll)
  },
  deactivated () {
    window.removeEventListener('scroll', this.handleScroll)
  }
}
</script>

<style lang="stylus" scoped>
@import '~styles/variables.styl';
.header-abs
  position absolute
  left .2rem
  top .2rem
  width .8rem
  height .8rem
  line-height .8rem
  text-align center
  border-radius .4rem
  background rgba(0, 0, 0, 0.8)
  .header-abs-back
    color #ffffff
    font-size 0.4rem
.header-fixed
    position fixed
    z-index 2
    left 0
    top 0
    right 0
    height $headerHeight
    line-height $headerHeight
    text-align center
    color #ffffff
    background $bgcolor
    font-size 0.32rem
    .header-fixed-back
        position absolute
        width 0.64rem
        text-align center
        font-size 0.4rem
        top 0
        left 0
        color #ffffff

</style>
